Ferrimannitol-ovalbumin (FMOA) is an adduct between ovalbumin and the complex Fe(III)-mannitol, useful as drug substance to correct haematological variables modified by loss and shortage of iron. There are various processes disclosed in the prior art for the preparation of this substance.
EP 0 875 249 B1 discloses a process for preparing complexes consisting of Fe(III), a polyhydroxylate compound and ovalbumin such as FMOA (see example 1).
Likewise, EP 1 655 308 B1 describes a procedure to obtain adducts of soluble ovalbumin with trivalent iron polyalcohol complexes comprising the treatment of ovalbumin with an alkaline protease which allows the elimination of the allergy and immunotoxicity problems associated with said albumin. Example 1 of EP 1 655 308 B1 is directed to FMOA.
The formulation of FMOA into a pharmaceutical composition entails several inconveniences. Firstly, as it is known, Fe has a distinctive metallic unpleasant taste that makes difficult to elaborate liquid dosage forms for oral administration well accepted by the patients. This unpleasant taste could be avoided with solid dosage forms, by either using excipients (e.g. flavors) to mask the iron taste and/or administering the same without their previous disintegration or dissolution. However, such forms would be hard to swallow because of their size. Furthermore, the FMOA is a dark-red, homogeneous substance with appearance of powder or of flakes, difficult to formulate as a solid dosage form, so that to date it has not been possible to obtain oral formulations in the form of tablets in a reliable and robust way.
FMOA is currently marketed for the treatment of ferropenic anemia and iron deficiency states exclusively as a granular composition which has to be dissolved in water: for instance, each sachet containing 600 mg of composition is poured into 200 ml of water and stirred until complete dissolution; the solution must be immediately consumed. As FMOA is usually prescribed to pregnant women, the intake of a granular formulation dissolved in water most often gives place to emetic events in this patient group. It is readily appreciated in this regard that a dosage form easy to intake and with pleasant taste would be essential with the aim of avoiding emesis in patients susceptible to emesis.
Accordingly, there is still a need to find a solid dosage form of ferrimannitol-ovalbumin useful as therapeutic for iron-deficiency anaemia and other related states that solve at the same time at least one of the problems associated with the formulations disclosed in the state of the art. Preferably, the pharmaceutical dosage formulation containing FMOA should show the following characteristics:                pleasant taste;        easy to intake;        proper dosage uniformity; and        robust manufacturing process.        